Sentence for word string

There are a few things of interest with your solution. Firstly, it is a very literal implementation of the problem to solve, and I worry that it is too literal. For example, are you sure that sentences end with just a period .? Is it not a period and some whitespace? Is a URL like example.com two sentences?

The second issue I have is the blind trust you have in the inputs. You happily convert the input text to lower-case (too often, actually), but you do not convert the word to lower-case. If someone gives an upper-case word, you’ll never find it.

I would prefer a more zen approach, using regular expressions… actually, just a split, and some Java 8 niceness.

private static final Pattern END_OF_SENTENCE = Pattern.compile("\.\s+");

public static String getSentence(String text, String word) {
    final String lcword = word.toLowerCase();
    return END_OF_SENTENCE.splitAsStream(text)
            .filter(s -> s.toLowerCase().contains(lcword))
            .findAny()
            .orElse(null);
}

Why is that better? Well, it streams the text in the form of sentences, and then finds the first match in a sentence. If there are no sentences, it matches the whole thing.

Note that the same principles can be used with a non-streaming approach. Split by sentences, then find the first match.

In an android environment, you could do:

private static final Pattern END_OF_SENTENCE = Pattern.compile("\.\s+");

public static String getSentence(String text, String word) {
    final String lcword = word.toLowerCase();
    for (String sentence : END_OF_SENTENCE.split(text)) {
        if (sentence.toLowerCase().contains(lcword)) {
            return sentence;
        }
    }
    return null;
}

Note that the results from the above code may, or may not include the terminating period. If the match is in the last sentence of a text, and that text ends with a period, then the period may be returned as part of the result. If there is a match in the middle of the text, then the period will not be included.

Synonym: bind, connect, line up, thread, tie. Antonym: unstring. Similar words: striking, strip, strike, strict, doctrine, restrict, district, strictly. Meaning: [strɪŋ]  n. 1. a lightweight cord 2. stringed instruments that are played with a bow 3. a tightly stretched cord of wire or gut, which makes sound when plucked, struck, or bowed 4. a sequentially ordered set of things or events or ideas in which each successive member is related to the preceding 5. a linear sequence of symbols (characters or words or phrases) 6. a tie consisting of a cord that goes through a seam around an opening 7. (cosmology) a hypothetical one-dimensional subatomic particle having a concentration of energy and the dynamic properties of a flexible loop 8. a collection of objects threaded on a single strand 9. a necklace made by a stringing objects together. v. 1. thread on or as if on a string 2. add as if on a string 3. move or come along 4. stretch out or arrange like a string 5. string together; tie or fasten with a string 6. remove the stringy parts of 7. provide with strings. 

Give a sentence, print different words present in it. Words are separated by space. 

Examples: 

Input : str = "Geeks for Geeks"
Output : Geeks
         for
         Geeks  
Explanation : All space separated words 
are printed line by line.

Input : str = "a computer science portal"
Output : a
         computer
         science
         portal

Method 1 (Writing our own logic):

We traverse through all characters. If current character is space, we have reached end of a word, we print current word and reset it to empty. Else we append current character to word. 

Implementation:

Complexity Analysis:

• Time complexity : O(n) 
• Auxiliary Space : O(n)

Method 2 (Using strtok()):

Implementation:

Note: strtok() function cannot be used with C++ STL string. It requires string to be character array.

Complexity Analysis:

• Time complexity : O(n) 
• Auxiliary Space : O(n)

Method 3 (Using stringstream):

Implementation:

Time complexity : O(n) 
Auxiliary Space : O(n)

Method 4 (Using std::getline() Function):

The C++ getline() is a standard library function that is used to read a string or a line from an input stream. It is a part of the <string> header.

Implementation

Time Complexity: O(N), where N is the length of the string.
Auxiliary Space: O(1).

Method 5 (Using Temporary String):

In C++, one approach is to use a temporary string to hold each word as it is extracted from the sentence. The sentence can be split into words by iterating over each character in the sentence and checking for whitespace characters. When a whitespace character is encountered, the temporary string is considered a word and can be added to a list of words. This process is repeated until all characters in the sentence have been processed.

Implementation

Time Complexity: O(N), where N is the length of the sentence.
Auxiliary Space: O(N)

Method 6 (Using find(), substr() and erase() Functions):

One approach is to use the find(), substr() and erase() functions to split a sentence into words in C++. 

Steps:

1. Initialises a string with the sentence and declares two variables for the position and the extracted word.
2. It then uses a while loop to find the spaces in the sentence and extract the words using the substr() function. 
3. Lastly, it prints out the last word of the sentence.

Implementation

Time Complexity: O(N), where N is the length of the sentence.
Auxiliary Space: O(1)